If you are reading a book, do read.

If you are doing some work, do work.

If you are checking emails and social media, do check emails and social media.

If you are chatting with a friend, do chat with a friend.

If you are in a meeting, do be in the meeting.

The point is that you should commit to whatever it is that you are doing at any given moment. Mixing different activities at the same time is a sure way to get nervous, stressed, and eventually achieve nothing.